For the purpose of precisely metering extremely high-quality media, for example in the pharmaceutical sector, elaborate and costly metering systems are usually employed which have to be cleaned and sterilized after the end of the process with high effort. This is profitable above all for larger sample quantities. In the processing of smaller quantities, however, this represents an undesired cost factor. This is why it is preferred to use disposable components for the metering of smaller media quantities, which can be changed after each run.
A metering unit of this type is described in DE 20 2012 003 948 U1. In the metering unit which is illustrated there, air as a control fluid is alternately blown into a pumping chamber and sucked out of it, so that a membrane is moved between two end positions and hence the volume of a metering chamber opposite the pumping chamber increases and decreases. This results in a membrane pump by means of which the metering fluid can be dosed in very precise quantities. The metering chamber which is shown there has its inlet and outlet sides fluidly connected to or separated from an inlet and outlet through a membrane valve each. The process of controlling the membrane valves is carried out, for example, by means of a pneumatic valve controlling the pressurization of the membrane on the part of the pumping chamber.
It is the object of the invention to provide a metering system which allows an extremely precise metering of a defined media quantity, with that part of the system which is in contact with the media being easily exchangeable and having such a simple construction that it can be produced at low cost and thus be designed as a disposable part.